SMS Deliverability Changes for Higher Education

What changed with SMS rules

Carriers and regulators now require more detailed registration, more explicit student consent, and stricter adherence to industry guidelines. Messages that do not meet these standards may be slowed, blocked, or filtered before they reach a recipient’s phone.

Key changes include:

• 100% blocking of unregistered A2P 10DLC traffic
• Stricter consent expectations
• New throughput (rate limit) caps
• Expanded registration and documentation requirements

Unregistered 10DLC messages are now blocked

As of February 2025, all major US carriers block unregistered A2P traffic using 10DLC (10-digit long code). If your institution sends messages from any unregistered campaign, those messages will not be delivered.

What this means for you:

• Every SMS campaign must be registered and approved under your institution’s brand.
• Even low-volume or “one-off” texting from 10-digit numbers must be associated with a registered A2P campaign.

If you are unsure whether your campaigns are registered, contact your internal technical team or your SMS provider.

Consent rules and expectations

The FCC proposed a stricter “one-to-one consent” standard, which would require recipients to agree to specific types of messages they will receive. Even though this proposal is not currently law, many carriers have adopted one-to-one consent as a business rule. 

For admissions offices, this means:

• General “text updates” language is no longer enough.
• Students should see clear descriptions such as “application reminders,” “event updates,” or “deadline alerts” when they opt in.

Update your inquiry forms, event registration pages, and application portals so they clearly state the types of SMS messages students will receive.

Throughput and message caps

Carriers introduced tighter throughput (sending rate) rules in 2025, which can affect high-volume or time-sensitive sends. For example, some carriers cap the number of messages per day at the brand level, while others cap the number of messages per minute at the campaign level. 

This can result in:

• Slower delivery during peak times, such as application deadlines or large event reminders.
• Messages queuing or failing if you send too many at once.

To reduce risk, plan to stagger your sends instead of sending all messages at a single peak time.

New registration and documentation requirements

From late 2025 into 2026, carriers and The Campaign Registry introduced additional requirements for A2P registration. These requirements are designed to verify senders' identities and make opt-in flows more transparent to students.

Requirements include:

• Verified business identity for your institution
• Employer Identification Number (EIN) for sole proprietors or similar entities
• Terms of Service (TOS) and Privacy Policy URLs on all opt-in pages
• Additional metadata for international numbers

Make sure your institutions’ opt-in mechanisms are documented and easy for students to understand.

Regulations that affect admissions messaging

Several regulations and industry guidelines shape how you must collect consent and send SMS:

• TCPA (Telephone Consumer Protection Act)
  
  • Governs consent, opt-ins, and opt-outs for marketing and informational SMS in the U.S.
  • Requires explicit permission before texting, written consent for marketing messages, and opt-out language such as “Reply STOP to unsubscribe” in your messages.
• FCC (Federal Communications Commission)
  
  • Enforces TCPA rules and defines what qualifies as express consent and acceptable opt-out mechanisms.
• CTIA Messaging Principles and Best Practices
  
  • Industry guidelines that carriers use for message filtering.
  • Emphasize transparent opt-in flows, clear sender identity, clear rules on prohibited content, and strict opt-out handling.

If your messages do not align with these standards, carriers may filter or block them.

Why your messages might not be delivered

You may see lower deliverability if one or more of these conditions apply:

• Your SMS brand or campaign registration is incomplete or outdated.
• Your opt-in language is generic and does not describe message types.
• Your sending volume exceeds carrier throughput caps during peak times.
• You sent from an unverified toll-free number or an unregistered 10DLC number.
• You do not maintain clear records of consent.
• Your message content appears “spam-like” to carrier filters (for example, too many links, all caps urgency, or repeated identical content). 

In these cases, messages may be blocked at the carrier level before reaching the student.

What you should do next

Use this checklist to improve SMS deliverability and compliance.

1. Review your opt-in workflows
   
   • Confirm that every opt-in page or form clearly lists the types of SMS messages students will receive.
   • Avoid vague phrases like “updates and information” without examples.
2. Surface your TOS and privacy policies
   
   • Ensure that your Terms of Service and Privacy Policy URLs appear prominently wherever students opt into SMS.
   • Verify that the policies reflect your SMS use (for example, reminders, alerts, or marketing).
3. Audit your message templates
   
   • Check that every template includes your institution’s name or a recognizable sender label.
   • Include opt-out language such as “Reply STOP to unsubscribe” in each message.
   • Avoid overly promotional language, multiple shortened links, or excessive urgency in a single message.
4. Plan your sending schedule
   
   • Avoid sending all messages at once, especially for large campaigns.
   • Stagger sends across several minutes or hours to stay within carrier caps and reduce the risk of queue overflow.

If your institution has an SMS governance or compliance contact, coordinate these updates with that person or team.

How we can support you

Our team can help your institution navigate these changes:

• Maintain compliant Twilio A2P connections for TargetX SMS and Comm Planner SMS. 
• Recommend best practices for consent language and opt-in flows that align with TCPA, FCC, and CTIA guidance.
• Assist with A2P 10DLC verification steps for TargetX-managed Twilio accounts.

If you need help reviewing your setup, open a support ticket and include recent examples of failed messages and any visible error codes.

Common Twilio SMS error codes

When an SMS fails, Twilio returns an error code that helps you understand what happened. The table below lists common codes related to SMS deliverability.

Error code	Description
21610	You tried to send to a recipient who has unsubscribed (for example, they replied STOP).
21611	The “From” number has exceeded the maximum number of queued messages.
21612	The message cannot be sent with the current “To” and “From” combination.
21614	The “To” number is not a valid mobile number.
21617	The message body is too long and exceeds the 1600 character limit.
30001	Queue overflow: too many messages sent too quickly.
30003	The destination handset is unreachable (for example, turned off or out of service).
30004	The carrier or destination number is blocking messages.
30005	The destination handset is unknown to the carrier.
30006	The number is a landline or the carrier is unreachable.
30007	Carrier violation: the carrier filtered the message (often for policy reasons).
30008	Unknown error occurred during delivery.
30032	The toll free number has not been verified.
30034	The message came from an unregistered A2P 10DLC number (U.S. only).
30500	Twilio internal error.
400	Bad request: the request to Twilio is invalid or malformed.
403	Forbidden: credentials or permissions are invalid.
21211	Invalid “To” phone number.
14108	The “From” phone number is not capable of sending SMS.

For the full Twilio error and warning dictionary, see the Twilio article Error Warning Dictionary.